On 2013/5/19 7:34, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
>
> As indicated by comments in mm/memory_hotplug.c:remove_memory(),
> if CONFIG_MEMCG is set, it may not be possible to offline all of the
> memory blocks held by one module (FRU) in one pass (because one of
> them may be used by the others to store page cgroup in that case
> and that block has to be offlined before the other ones).
>
> To handle that arguably corner case, add a second pass of companion
> device offlining to acpi_scan_hot_remove() and make it ignore errors
> returned in the first pass (and make it skip the second pass if the
> first one is successful).
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> ---
> drivers/acpi/scan.c | 67 ++++++++++++++++++++++++++++++++++++++--------------
> 1 file changed, 50 insertions(+), 17 deletions(-)
>
> Index: linux-pm/drivers/acpi/scan.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/scan.c
> +++ linux-pm/drivers/acpi/scan.c
> @@ -131,6 +131,7 @@ static acpi_status acpi_bus_offline_comp
> {
> struct acpi_device *device = NULL;
> struct acpi_device_physical_node *pn;
> + bool second_pass = (bool)data;
> acpi_status status = AE_OK;
>
> if (acpi_bus_get_device(handle, &device))
> @@ -141,15 +142,26 @@ static acpi_status acpi_bus_offline_comp
> list_for_each_entry(pn, &device->physical_node_list, node) {
> int ret;
>
> + if (second_pass) {
> + /* Skip devices offlined by the first pass. */
> + if (pn->put_online)
should it be "if (!pn->put_online)" ?
Thanks
Xishi Qiu
> + continue;
> + } else {
> + pn->put_online = false;
> + }
> ret = device_offline(pn->dev);
> if (acpi_force_hot_remove)
> continue;
>
> - if (ret < 0) {
> - status = AE_ERROR;
> - break;
> + if (ret >= 0) {
> + pn->put_online = !ret;
> + } else {
> + *ret_p = pn->dev;
> + if (second_pass) {
> + status = AE_ERROR;
> + break;
> + }
> }
> - pn->put_online = !ret;
> }
>
> mutex_unlock(&device->physical_node_lock);
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